1. Field of the Invention
The present invention relates to a novel ailanthone derivative having an antineoplastic activity.
2. Description of the Prior Art
Various attempts have been heretofore made to evaluate antineoplastic or antitumor effects of natural substances and compounds derived from natural substances. Of these substances and compounds, some have been clinically used as an antineoplastic or antitumor agent. However, these agents are still insufficient for clinical use in view of either their effects or toxicity. That is, the effective agents generally have the disadvantage of toxicity, while less toxic agents are less effective.
Of these natural substances, it is known that bruceantin having the general formula (2): ##STR4## is included in Brucea antidysenterica Mill belonging to Simarubaceae, which has been used for curing cancer in Ethiopia, as disclosed in Kupchans et al, J. Org. Chem., 38, 178 (1973), J. Org. Chem., 40, 648 (1975), U.S. Pat. No. 3,969,369, and British Pat. No. 144094. Then, various quassinoid compounds such as bruceoside A, dehydroailanthinone, glaucarubinone have been synthesized and the antitumor effects thereof have been evaluated as disclosed in J. Org. Chem., 40, 654 (1975), ibid 44, 2180 (1979), J. Pharm. Sci., 68, 883 (1979), and Cancer Treatment Reports, 60, 1031 (1976). However, these quassinoid compounds are still not sufficient from the viewpoints of their effectiveness and toxicity.